Control method and device of water chilling unit and system

Abstract

The invention provides a control method and device of a water chilling unit and a system. The control method is applied to a controller of an air conditioning system, the air conditioning system comprises a cooling tower, a plate heat exchanger, the water chilling unit and the controller, and the water chilling unit comprises a condenser and an evaporator. A lower tower header pipe of the cooling tower is connected with the plate heat exchanger, an upper tower header pipe of the cooling tower is connected with the water chilling unit, the plate heat exchanger is connected with the water chilling unit, and the controller is connected with a temperature sensor at an inlet of the condenser, a temperature sensor at an inlet of the evaporator, the cooling tower and the plate heat exchanger. The controller obtains inlet temperature values of the evaporator and the condenser and the flow of the freezing side of the water chilling unit in real time, the inlet temperature of the freezing side of the water chilling unit is adjusted by adjusting an adjusting valve on the cooling side of the plate heat exchanger, and the inlet temperature of the cooling side of the water chilling unit is adjusted by adjusting the rotating speed of a cooling fan of the cooling tower. According to the method, the load rate of the water chilling unit is not lower than the minimum load rate, and it is guaranteed that surge of the water chilling unit is avoided.

Description

technical field [0001] The present application relates to the technical field of air conditioning, and in particular to a control method, device and system of a chiller. Background technique [0002] In occasions where refrigeration is required all year round, for an air conditioning system composed of chillers, plate heat exchangers, cooling towers, water pumps, etc., when the outdoor temperature drops, the plate heat exchangers and cooling towers can be used to partially cool the chilled water in advance. Then let the chilled water enter the chiller, and the chiller will reduce the temperature of the chilled water to the set temperature. This mode of operation is generally referred to as a semi-free cooling mode. [0003] In the semi-free cooling mode, in order to make the plate heat exchanger contribute more load, it is necessary to reduce the water temperature of the lower tower of the cooling tower, but too low water temperature of the lower tower will not only reduce ...

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Problems solved by technology

[0003] In the semi-free cooling mode, in order to make the plate heat exchanger contribute more load, it is necessary to reduce the water temperature of the lower tower of the cooling tower, but too low water temperature of the lower tower will not only reduce the load rate of the chiller to the minimum load rate, but also It will reduce the temperature of the water flowing into the condenser of the chiller to its limit value, which will cause the condensing pressure to be too low and prevent the chiller from working properly

[0004] At present, for the control of semi-free cooling conditions, manual debugging is used to ensure the minimum load rate of the chiller. There is no clear quantitative index for control, and the normal operation of the chiller cannot be fully guaranteed.

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